I fitted the universal K&N conical air filter to my 2.5L V6. Had it for about 2 years and recently changed back to OEM system including the snorkle to front fender area.
Here are my thoughts in no order of importance:
Pro's - Induction sound is 'muscular'
There is 'wow' factor with hood open(rarely)
Con's - When not in the mood, induction sound is noisy
Air intake temperature sensor has no place to firmly mont
There is no perceived power increase, fuel economy improvement
Back-of-mind worry about water ingestion in rain
More sensitivity to underhood air temperature
Back-of-mind worry about oiling too much after cleaning
All in all, con's weighed more than pro's and I reverted back to disposable factory filter set up. Just my 2 cents over last 2 years of having the K&N in my Contour.